This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. We have selected almost 400 target genes from Mycobacterium tuberculosis for cloning, expression and crystal structure determination. The targets are either gene products with an unknown function or are enzymatic activities from several essential pathways involved in detoxification or amino acid synthesis. 15 crystal structures have been determined to date and a number of targets haven been cloned, expressed and crystallized. Structural work is continuing on the previously determined crystal structures with the goal of elucidating the detailed enzymatic mechanism for the design of effective inhibitors. The project requires the screening of typically large numbers of crystals, MAD or SAD phasing and high-resolution data collection to visualize the details of substrate or inhibitor binding.